JavaScript Methods

JavaScript Methods : In JavaScript, there are many implicit techniques. For instance, Here, the parseInt() method of the Number article is utilized to change over numeric string worth to a whole number worth. To get familiar with worked-in strategies, visit JavaScript Built-In Methods.

Perhaps you don’t care for bolt works, you would prefer not to invest an excess of energy discovering some new information, or they’re simply not important for you. Relax, you are in good company. I’ll show you how it is done in ES5 (practical deceleration) and ES6 (bolt works).

Know: Arrow capacities and capacity statements/articulations are not same and can’t be supplanted aimlessly. Remember that the this watchword works diversely between the two.

How to use Method

Item Methods in JavaScript can be gotten to by utilizing capacities. Capacities in JavaScript are put away as property estimations. The items can likewise be called without utilizing section (). In a technique, ‘this’ alludes to the proprietor object. Extra data can likewise be added alongside the article technique. Language structure: objectName.methodName()

Concat():

const a = ["Rohit Gautam", "Ajit"];
const b = ["Sandeep", "Alok", "Ankit"];
const c = ["Amit"];
const children = a.concat(b, c);
console.log(children);
// Output 
(6) ["Rohit Gautam", "Ajit", "Sandeep", "Alok", "Ankit", "Amit"]

Copywithin():

const persons = ["Rohit Gautam", "Ajit", "Alok", "Ankit"];
const copy = persons.copyWithin(2, 0);
console.log(copy);

//Output
(4) ["Rohit Gautam", "Ajit", "Rohit Gautam", "Ajit"]

entries() :

The Array.entries() method returns an Array Iterator object with key/value pairs:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
const f = fruits.entries();
console.log(f);
for (let x of f) {
console.log(x);
}

//Ouput 
Array Iterator {}
[0, "Banana"]
[1, "Orange"]
[2, "Apple"]
[3, "Mango"]

every():

Check if all the values in number[] are 10 or greater:

 const number= [32, 33, 16, 40];
 console.log(number.every(checkNumber));

 function checkNumber(age) {
 return age > 10;
 }

//output
true

fill():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
console.log(fruits.fill("Kiwi"))
//output
Kiwi,Kiwi,Kiwi,Kiwi

filter():

const ages = [32, 33, 16, 40];

console.log(ages.filter(checkAdult));

function checkAdult(age) {
  return age >= 18;
}
//output
32,33,40

find():

const ages = [3, 10, 18, 20];

function checkAge(age) {
  return age > 18;
}

function myFunction() {
  console.log(ages.find(checkAge));
}

//output 
20

findIndex():

const ages = [3, 10, 18, 20];

console.log(ages.findIndex(checkAge));

function checkAge(age) {
  return age > 18;
}
//output
3

forEach():

let text = "";
const fruits = ["apple", "orange", "cherry"];
fruits.forEach(myFunction);

console.log(text);
 
function myFunction(item, index) {
  text += index + ": " + item + "<br>"; 
}
//output
0: apple
1: orange
2: cherry

from()

const myArr = Array.from("ABCDEFG");
console.log(myArr);
//output
A,B,C,D,,E,F,G

includes():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
console.log(fruits.includes("Mango"));
//output
true

indexOf():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.indexOf("Apple")   // Returns 2
//output
2

isArray()

const fruits = ["Banana", "Orange", "Apple", "Mango"];
Array.isArray(fruits)   // Returns true
//output
true

join():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
console.log(fruits.join());
// output
Banana,Orange,Apple,Mango

keys():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
const keys = fruits.keys();

let text = "";
for (let x of keys) {
  text += x + "<br>";
}
console.log(text );
//output
0
1
2
3

lastIndexOf()

const fruits = ["Apple", "Orange", "Apple", "Mango"];
fruits.lastIndexOf("Apple")   ;

//output
2

map():

const numbers = [4, 9, 16, 25];
console.log(numbers.map(Math.sqrt));
//output
2,3,4,5

pop():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.pop();   // Removes "Mango"

//output
"Banana", "Orange", "Apple"

push()

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.push("Kiwi");   // Adds "Kiwi"

//output
Banana,Orange,Apple,Mango,Kiwi

reduce():

const numbers = [275, 50, 25];

numbers.reduce(myFunc);

function myFunc(total, num) {
  return total - num;
}

//output
200

reduceRight():

const numbers = [175, 50, 25];

numbers.reduceRight(myFunc);

function myFunc(total, num) {
  return total - num;
}
//output
-200

reverse():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.reverse();
//output
Mango,Apple,Orange,Banana

shift():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.shift();
//output
Orange,Apple,Mango

slice():

const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
const citrus = fruits.slice(1, 3);
//output
Orange,Lemon

some()

const ages = [3, 10, 18, 20];

ages.some(checkAdult)   // Returns true

function checkAdult(age) {
  return age >= 18;
}
//output
true

sort():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.sort();
//output
Apple,Banana,Mango,Orange

splice():

const fruits = ["Banana", "Orange", "Apple", "Mango"];

// At position 2, add 2 elements: 
fruits.splice(2, 0, "Lemon", "Kiwi");

//ouput
Banana,Orange,Lemon,Kiwi,Apple,Mango

toString():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
let text = fruits.toString();
//output
Banana,Orange,Apple,Mango

unShift():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.unshift("Lemon","Pineapple");
//output
Lemon,Pineapple,Banana,Orange,Apple,Mango

valueOf():

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.valueOf();   // Returns fruits
//output
Banana,Orange,Apple,Mango

 

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